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L I. IS.Q.OLAQ/ 1036- 74 ///_ 



1 

SOLAR/1030-79/14 



^ 



Solar Energy System 
Performance Evaluation 



CHESTER WEST 

SINGLE- FAMILY RESIDENCE 

Huntsville, Alabama 

September 1978 Through March 1979 




U.S. Department of Energy 

National Solar Heating and 
Cooling Demonstration Program 

National Solar Data Program 




NOTICE 

This report was prepared as an account of work sponsored by the United States 
Government. Neither the United States nor the United States Department of Energy, nor 
any of their employees, nor any of theii contractors, subcontractors, or their employees, 
makes any warranty, express or implied, or assumes any legal liability or responsibility for 
the accuracy, completeness or usefulness of any information, apparatus, product or process 
disclosed, or represents that its use would not infringe privately owned rights. 



This report has been reproduced directly from the best available copy. 



Available from the National Technical Information Service, U. S. Department of 
Commerce, Springfield, Virginia 22161. 



Price: Paper Copy $5.25 
Microfiche S3.00 



SOLAR/1030-79/14 

Distribution Category UC-59 



SOLAR ENERGY SYSTEM PERFORMANCE EVALUATION 



CHESTER WEST 
HUNTSVILLE, ALABAMA 



SEPTEMBER 1978 THROUGH MARCH 1979 



NORMAN M. LABBE, PRINCIPAL AUTHOR 
JERRY T. SMOK, MANAGER OF RESIDENTIAL SOLAR ANALYSIS 
LARRY J. MURPHY, IBM PROGRAM MANAGER 



IBM CORPORATION 
18100 FREDERICK PIKE 
GAITHERSBURG, MARYLAND 20760 



PREPARED FOR 

THE DEPARTMENT OF ENERGY 

OFFICE OF ASSISTANT SECRETARY FOR 

CONSERVATION AND SOLAR APPLICATION 

UNDER CONTRACT EG-77-C-01-4049 

H. JACKSON HALE, PROGRAM MANAGER 



TABLE OF CONTENTS 



1 . FOREWORD 

2. SUMMARY AND CONCLUSIONS 

2.1 Performance Summary 

2.2 Conclusions 

3. SYSTEM DESCRIPTION 

4. PERFORMANCE EVALUATION TECHNIQUES 

5. PERFORMANCE ASSESSMENT 

5.1 Weather Conditions 

5.2 System Thermal Performance 

5.3 Subsystem Performance 

5.3.1 Collector Array and Storage Subsystem 

5.3.1.1 Collector Array 

5.3.1.2 Storage . . 

5.3.2 Domestic Hot Water (DHW) Subsystem 

5.3.3 Space Heating Subsystem 

5.4 Operating Energy 

5.5 Energy Savings 

6. REFERENCES 

APPENDIX A DEFINITIONS OF PERFORMANCE FACTORS AND SOLAR TERMS 
APPENDIX B SOLAR ENERGY SYSTEM PERFORMANCE EQUATIONS 
APPENDIX C LONG-TERM AVERAGE WEATHER CONDITIONS 

APPENDIX D MONTHLY SOLAR ENERGY DISTRIBUTION FLOWCHARTS 
APPENDIX E MONTHLY SOLAR ENERGY DISTRIBUTIONS 



Page 

1-1 

2-1 

2-1 

2-3 

3-1 

4-1 

5-1 

5-2 

5-4 

5-8 

5-8 

5-8 

5-12 

5-16 

5-18 

5-18 

5-21 

6-1 

A-l 

B-l 

C-l 

D-l 

E-l 



n 



LIST OF ILLUSTRATIONS 

FIGURES TITLE PAGE 

3-1 Solar Energy System Schematic 3-2 

5-1 Solar Energy Distribution Flowchart Summary 5-6 

D-l Solar Energy Distribution Flowchart - D-2 

September 1978 

D-2 Solar Energy Distribution Flowchart - D-3 

October 1978 

D-3 Solar Energy Distribution Flowchart - D_ 4 

November 1978 

D-4 Solar Energy Distribution Flowchart - D-5 

December 1978 

D-5 Solar Energy Distribution Flowchart - D-6 

January 1979 

D-6 Solar Energy Distribution Flowchart - D ~? 

February 1979 

D-7 Solar Energy Distribution Flowchart - D-8 

March 1979 



m 



LIST OF TABLES 

TABLES TITLE PAGE 

5-1 Weather Conditions 5-3 

5-2 System Thermal Performance Summary 5-5 

5-3 Solar Energy Distribution Summary 5-7 

5-4 Solar Energy System Coefficient of Performance 5-9 

5-5 Collector Array Performance 5-10 

5-6 Storage Performance 5-13 

5-7 Solar Energy Losses - Storage and Transport 5-14 

5-8 Domestic Hot Water Subsystem Performance 5-17 

5-9 Space Heating Subsystem Performance 5-19 

5-10 Operating Energy 5-20 

5-11 Energy Savings 5-22 

E-l Solar Energy Distribution - E-2 

September 1978 

E-2 Solar Energy Distribution - E-3 

October 1978 

E-3 Solar Energy Distribution - E-4 

November 1978 

E-4 Solar Energy Distribution - E-5 

December 1978 

E-5 Solar Energy Distribution - E-6 

January 1979 

E-6 Solar Energy Distribution - E-7 

February 1979 

E-7 Solar Energy Distribution - E-8 

March 1979 



IV 



NATIONAL SOLAR DATA PROGRAM REPORTS 



Reports prepared for the National Solar Data Program are numbered under 
specific format. For example, this report for the Chester West project site 
is designated as SOLAR/1030-79/14. The elements of this designation are 
explained in the following illustration. 



SO 



Prepared for the 

National Solar 

Data Program 



Demonstration Site 



AR/1030-79/14 



Report Type 
Designation 



Year 



o Demonstration Site Number: 

Each project site has its own discrete number - 1000 through 1999 for 
residential sites and 2000 through 2999 for commercial sites. 

o Report Type Designation: 



This number identifies the type of report, e.g., 

Monthly Performance Reports are designated by the numbers 01 (for 
January) through 12 (for December). 

Solar Energy System Performance Evaluations are designated by the 
number 14. 



Solar Project Descriptions are designated by the number 50. 

Solar Project Cost Reports are designated by the number 60. 

These reports are disseminated through the U. S. Department of Energy Technical 
Information Center, P. 0. Box 62, Oak Ridge, Tennessee 37830. 



VI 



1 . FOREWORD 

The National Program for Solar Heating and Cooling is being conducted by the 
Department of Energy under the Solar Heating and Cooling Demonstration Act of 
1974. The overall goal of this activity is to accelerate the establishment 
of a viable solar energy industry and to stimulate its growth to achieve a 
substantial reduction in nonrenewable energy resource consumption through 
widespread applications of solar heating and cooling technology. 

Information gathered through the Demonstration Program is disseminated in a 
series of site-specific reports. These reports are issued as appropriate and 
may include such topics as: 

o Solar Project Description 

o Design/Construction Report 

o Project Costs 

o Maintenance and Reliability 

o Operational Experience 

o Monthly Performance 

o System Performance Evaluation 

The International Business Machines (IBM) Corporation is contributing to the 
overall goal of the Demonstration Act by monitoring, analyzing, and reporting 
the thermal performance of solar energy systems through analysis of measurements 
obtained by the National Solar Data Program. 

The Solar Energy System Performance Evaluation Report is a product of the 
National Solar Data Program. Reports are issued periodically to document the 
results of analysis of specific solar energy system operational performance. 
This report includes system description, operational characteristics and 
capabilities, and an evaluation of actual versus expected performance. The 
Monthly Performance Report, which is the basis for the Solar Energy System 
Performance Evaluation Report, is published on a regular basis. Each para- 
meter presented in these reports as characteristic of system performance 



1-1 



represents over 8,000 discrete measurements obtained each month by the National 
Solar Data Network (NSDN). Documents referenced in this report are listed in 
Section 6, "References." Numbers shown in brackets refer to reference numbers 
in Section 6. All other documents issued by the National Solar Data Program 
for the Chester West solar energy system are listed in Section 7, "Biblio- 
graphy." 

This Solar Energy System Performance Evaluation Report presents the results 
of a thermal performance analysis of the Chester West solar energy system. 
The analysis covers operation of the system from September 1978 through 
March 1979. The Chester West solar energy system provides space heating and 
domestic hot water to a single-family dwelling located in Huntsville, Alabama. 
Section 2 presents a summary of the overall system results. A system descrip- 
tion is contained in Section 3. Analysis of the system thermal performance 
was accomplished using a system energy balance technique described in Section 
4. Section 5 presents a detailed assessment of the individual subsystems 
applicable to the site. 

The measurement data for the reporting period was collected by the NSDN [1]. 
System performance data are provided through the NSDN via an IBM-developed 
Central Data Processing System (CDPS) [2]. The CDPS supports the collection 
and analysis of solar data acquired from instrumented systems located through- 
out the country. This data is processed daily and summarized into monthly 
performance reports. These monthly reports form a common basis for system 
evaluation and are the source of the performance data used in this report. 



1-2 



2. SUMMARY AND CONCLUSIONS 

This section provides a summary of the performance of the solar energy system 
installed at Chester West, located in Huntsville, Alabama for the period 
September 1978 through March 1979. This solar energy system is designed to 
support the domestic hot water and space heating loads. A detailed descrip- 
tion of Chester West solar energy system operation is presented in Section 3. 

2.1 Performance Summary 

The solar energy site was occupied from September 1978 through March 1979 and 
the solar energy system operated continuously during most of this reporting 
period. The periods of non-operation were as follows: 

November 1 until November 8. A safety switch activated causing 
collector draindown. The system was recharged with a new solution on 
November 8. 

The DHW subsystem was turned off from March 7 through March 26. DHW 
control maintenance on March 27 restored it to operation. 

The total incident solar energy was 57.50 million Btu, of which 21.32 million 
Btu were collected by the solar energy system. Solar energy satisfied 74^ ' 
percent of the DHW requirements and 15 percent of the space heating require- 
ments. The space heating subsystem provided an electrical energy savings of 
3.31 million Btu. 

The overall weather conditions in Huntsville were s/ery close to what was 
expected during the period covered by the report. The average ambient tempera- 
ture of 52°F was exactly the same as the long-term average for the same period, 



Weighted average based on 3-month data: September, October, November (1978) 



2-1 



Heating and cooling degree-days of 3054 and 379 compared closely with long- 
term averages of 3125 and 347, respectively. Lastly, the site-measured 
average daily total incident solar energy on the collector array of 1201 
Btu per square foot per day was about the same as the predicted 1224 Btu 
per square foot per day. However, there was quite a bit of variation when 
comparing measured and predicted heating degree-days and incident solar 
energy availability on a month-to-month basis. This fact is noted in the 
discussion of the space heating solar fraction which follows shortly. 

The average efficiency of the collector array during the reporting period was 
37 percent. This 37 percent is the ratio of collected energy to total energy 
incident on the array. The month-to-month efficiency ranged from a low of 24 
percent in November to a high of 48 percent in December. 

Average storage efficiency was based on September, October and November data. 
(See Section 2.2, for why the other months were excluded). There was an 
average storage efficiency of 53 percent. In the three months available, a 
trend toward an increase in efficiency from September to November was noted 
(29 percent, to 60 percent, to 88 percent). Heavier cold weather loads could 
account for this increased efficiency. It is quite likely the trend continued 
into the winter months and reversed itself as spring approached. This explana- 
tion is reinforced by the storage average temperatures. There was an overall 
storage average temperature of 123°F. Storage averaged 158°F in September, 
was down in the 80' s and 90' s in December through February, and had climbed 
to an average of 127°F in March. The installation of the new storage tank in 
March (see Section 2.2) would partially account for the rise in temperature 
in March. 

The space heating solar fraction grew smaller as the outside ambient tempera- 
ture became lower and the space heating load increased. The solar energy 
system was always supportive during the entire reporting period. The system 
experienced greater and greater difficulty in meeting the increasing winter 
space heating load demands using solar energy with a consequent rise in 
auxiliary thermal requirements. This is especially evident in January and 



2-2 



February, which had solar fractions of 6 percent and 10 percent, respectively. 
Over 65 percent of the space heating load over the 7-month reporting period 
occurred during these two months. Three factors can be offered as a partial 
explanation. More solar energy should have been available. Incident solar 
energy availability was much lower in January and February than in any other 
month of the 7-month period (see Table 5-1). In addition, both were sub- 
stantially lower than the expected values. Consequently, solar energy col- 
lected values would unexpectedly be reduced during these months of high load. 
A second factor was the much higher than expected heating degree-days in 
January and February (see Table 5-1). The third factor was the condition of 
the original thermal storage tank, which was replaced in March (see Section 
2.2). It is quite likely that unmeasured solar energy tank losses did occur, 
and at an increased rate as the weather grew colder. 

2.2 Conclusions 

Solar Energy System Controls . Less than optimum control settings 
allowed the DHW pumps to stay on longer than necessary during most of the 
reporting period. This condition was rectified late in March. The primary 
effect this condition exerted on the DHW subsystem was twofold: (1) the DHW 
operational energy requirements were slightly higher than required; and (2) a 
small amount of thermal energy was extracted from the DHW subsystem through 
the storage to DHW heat exchanger. 

Thermal Storage Tank . A new galvanized steel tank, with external fiber 
glass insulation, was installed on March 1. The original fiberglass tank 
showed external signs of deterioration as reflected in observable water 
seepage. This condition naturally led to some thermal loss from storage. 

Collector Loop . A safety switch was inadvertently activated on November 1, 
causing the collector solution to drain. The solar energy system was off 
from November 1 until November 8, at which time the collector loop was re- 
filled with water. The loop was charged with the normal Solaryard G solution 
on November 9. Another drain-down occurred on November 19, at which time the 



2-3 



loop was refilled with water. On November 20 the collector loop was refilled 
with an ethylene-glycol (32 percent)/water solution. This solution was 
replaced by a Solaryard G solution on March 2. At the same time, a backup 
battery powered system was installed. 

The variety of fluids used in the collector loop provided different thermal 
transfer rates at different times. The backup battery power source greatly 
reduces the chances of a collector drain-down, when the normal power source 
fails. 

Data Sensors . The two liquid flowmeters (one in the DHW loop and the 
other in the space heating loop) downstream from the thermal storage tank 
provided unreliable data from December through March. Debris from the orig- 
inal fiberglass tank and deposits attributed to the corrosive reaction of the 
liquid, and metals in these loops fouled the target area of both flowmeters. 

Investigations are underway to select the best approach to clear the lines of 
debris and impede the corrosive reaction. In the interim, although the per- 
formance evaluation of the DHW and ECSS subsystems were limited, the evalua- 
tion of the space heating subsystem was unaffected. A complete evaluation of 
this latter subsystem was possible using flowrate data from the air side of 
the storage to space heating heat exchanger. 



2-4 



3. SYSTEM DESCRIPTION 

The Chester West site is a single-family residence in Huntsville, Alabama. 
Solar energy is used for space heating the home and preheating domestic hot 
water (DHW). The solar energy system has an array of flat-pi ate j col 1 ectors 
with a gross area of 225 square feet. The array faces south at an angle of 
49 degrees to the horizontal. A gl ycerol -water solution is used as the medium 
for delivering solar energy from the collector array to storage; water is the 
medium for delivering solar energy from storage to the space heating and hot 
water loads. Solar energy is stored aboveground in a 500-gall on water storage 
tank. Auxiliary space heating is provided by an air- to-air heat pump a nd 
electrical heating elements which are designed to function in parallel with 
the solar energy space heating loop. Auxiliary hot water heating is provided 
in series with the solar energy DHW loop through the use of electrical heating 
elements in an 80-gallon DHW tank. The system, shown schematically in 
Figure 3-1, has three modes of solar operation. 

Mode 1 - Collector-to-Storage : This mode activates when the control system 
senses a sufficient temperature difference between the collector and storage 
and remains active until the temperature difference drops below the accepted 
minimum. The collected energy is transferred to storage through a ring-type, 
liquid-to-liquid heat exchanger located in the storage tank. Pump PI is 
operating. 

Mode 2 - Storage- to-Space Heating : This mode activates when there is a demand 
for space heating. Solar energy is circulated to the conditioned space by 
solar-heated water from storage through a liquid-to-air heat exchanger located 
in the air-distribution duct. Pump P3 is operating. 

Mode 3 - Storage- to-DHW Tank : This mode activates when the control system 
senses a sufficient temperature difference between storage and the DHW tank, 
and remains active as long as a sufficient temperature difference exists. 
Water circulates from the top of storage through a liquid-to-liquid heat 
exchanger located in the bottom of the DHW tank. Pump P2 is operating. 



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4. PERFORMANCE EVALUATION TECHNIQUES 

The performance of the Chester West solar energy system is evaluated by 
calculating a set of primary performance factors which are based on those 
proposed in the intergovernmental agency report "Thermal Data Requirements 
and Performance Evaluation Procedures for the National Solar Heating and 
Cooling Demonstration Program" [3]. These performance factors quantify the 
thermal performance of the system by measuring the amount of energies that 
are being transferred between the components of the system. The performance 
of the system can then be evaluated based on the efficiency of the system in 
transferring these energies. All performance factors and their definitions 
are listed in Appendix A. 

Data from monitoring instrumentation located at key points within the solar 
energy system are collected by the National Solar Data Network. This data is 
first formed into factors showing the hourly performance of each system com- 
ponent, either by summation or averaging techniques, as appropriate. The 
hourly factors then serve as a basis for calculating the daily and monthly 
performance of each component subsystem. The performance factor equations 
for this site are listed in Appendix B. 

Each month, as appropriate, a summary of overall performance of the Chester 
West site and a detailed subsystem analysis are published. These monthly 
reports for the period covered by this Solar Energy System Performance Evalua- 
tion (September 1978 through March 1979) are available from the Technical 
Information Center, Oak Ridge, Tennessee 37830. 

In the tables and figures in this report, an asterisk indicates that the 
value is not available for that month; N.A. indicates that the value is not 
applicable for this site. 



4-1 



5. PERFORMANCE ASSESSMENT 

The performance of the Chester West solar energy system has been evaluated 
for the September 1978 through March 1979 time period. Two perspectives were 
taken in this assessment. The first views the overall system in which the 
total solar energy collected, the system load, the measured values for solar 
energy used, and system solar fraction are presented. Where applicable, the 
expected values for solar energy used and system solar fraction are also 
shown. The expected values have been derived from a modified f-chart analysis 
which uses measured weather and subsystem loads as input. The f-chart is a 
performance estimation technique used for designing solar heating systems. 
It was developed by the Solar Energy Laboratory, University of Wisconsin - 
Madison. The system mode used in the analysis is based on manufacturer's 
data and other known system parameters. In addition, the solar energy system 
coefficient of performance (COP) at both the system and subsystem level has 
been presented. 

The second view presents a more in-depth look at the performance of individual 
subsystems. Details relating to the performance of the collector array and 
storage subsystems are presented first, followed by details pertaining to the 
space heating and domestic hot water (DHW) subsystems. Included in this 
section are all parameters pertinent to the operation of each individual 
subsystem. 

In addition to the overall system and subsystem analysis, this report' also 
describes the equivalent energy savings contributed by the solar energy 
system. The overall system and individual subsystem energy savings are 
presented in Section 5.5. 

The performance assessment of any solar energy system is highly dependent on 
the prevailing weather conditions at the site during the period of performance, 
The original design of the system is generally based on the long-term averages 
for available insolation and temperature. Deviations from these long-term 
averages can significantly affect the performance of the system. Therefore, 



5-1 



before beginning the discussion of actual system performance, a presentation 
of the measured and long-term averages for critical weather parameters has 
been provided. 

5.1 Weather Conditions 

Monthly values of the total solar energy incident in the plane of the col- 
lector array and the average outdoor temperature measured at the Chester West 
site during the reporting period are presented in Table 5-1. Also presented 
in Table 5-1 are the corresponding long-term average monthly values of the 
measured weather parameters. These data are taken from Reference Monthly 
Environmental Data for Systems in the National Solar Data Network [4]. A 
complete yearly listing of these values for the site is given in Appendix C. 

During September 1978 through March 1979 the average daily total incident 
solar energy on the collector array was 1201 Btu per square foot per day. 
This was about the same as the estimated average daily solar radiation for 
this geographical area during the reporting period of 1224 Btu per square 
foot per day for a south-facing plane with a tilt of 49 degrees to the hori- 
zontal. The average ambient temperature during September 1978 through 
March 1979 was 52°F as compared with the long-term average of 52°F during 
the same period. The number of heating degree-days for the same period 
(based on a 65°F reference) was 3054, as compared with the summation of the 
long-term averages of 3125. The number of cooling degree-days for the same 
period (based on a 65°F reference) was 379, as compared with the summation of 
the long-term averages of 347. 

Monthly values of heating and cooling degree-days are derived from daily 
values of ambient temperature. They are useful indications of the system 
heating and cooling loads. Heating degree-days and cooling degree-days are 
computed as the difference between daily average temperature and 65°F. For 
example, if a day's average temperature was 60°F, then five heating degree- 
days are accumulated. Similarly, if a day's average temperature was 80°F, 
then 15 cooling degree-days are accumulated. The total number of heating and 
cooling degree-days is summed monthly. 



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5-3 



5.2 System Thermal Performance 

The thermal performance of a solar energy system is a function of the total 
solar energy collected and applied to the system load. The total system load 
is the sum of the useful energy delivered to the loads (excluding losses in 
the system), both solar and auxiliary thermal energies. The portion of the 
total load provided by solar energy is defined as the solar fraction of the 
load. 

The thermal performance of the Chester West solar energy system is presented 
in Table 5-2. This performance assessment is based on the 7-month period 
from September 1978 to March 1979. During the reporting period, a monthly 
average of 3.05 million Btu of solar energy was collected and the average 
system load was 4.90 million Btu. The average measured amount of solar 
energy delivered to the load subsystem was 1.48 million Btu or 0.22 million 
Btu less than the expected average value. The measured average system solar 
fraction was 61 percent as compared to an expected value of 77 percent. Note 
that the solar energy used and solar fraction values were based on averages 
which included only September, October and November 1978. 

Figure 5-1 illustrates the flow of solar energy from the point of collection 
to the various points of consumption and loss for the reporting period. The 
numerical values account for the quantity of energy corresponding with the 
transport, operation, and function of each major element in the Chester West 
solar energy system for the total reporting period. 

Solar energy distribution flowcharts for each month of the reporting period 
are presented in Appendix D. 

Table 5-3 summarizes solar energy distribution and provides a percentage 
breakdown. Appendix E contains the monthly solar energy percentage distri- 
butions. 



5-4 





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5-5 



FIGURE 5-1. SOLAR ENERGY (MILLION BTU) DISTRIBUTION FLOWCHART - SUMMARY 

CHESTER WEST 



incident 
Solar Energy 






Solar Energy 
Storage Losses 


57.50 








* 


i 








(1) 






Change in 
Stored Energy 






Operational 
Incident 
Solar Energy 




Transport Loo 
Collector to 
Storage 


ECSS Subsystem 
Operating Energy 












0.23 










46.71 


* 


1.67 




1 






1 
















i 
1 

1 






Collected 
Solar Energy 








Solar Energy 
to Storage 


Solar Energy 
from Storage 










21.32 






(1) 


• 






id 


• 








Transport Lou 
Collector to DHW 








Transport Loss 
Storage to DHW 


















N.A. 








N.A. 














Domestic Hot 
Water Solar 
Energy Used 


























N.A. 


* 






DHW Subsystem 
Operating Energy 




Domestic Hot 
Water Auxiliary 
Thermal Used 






1.48 


• 










Domestic Hot 
Water Load 










(1) 




* 






tit 








Transport Loss 
Collector to 
Space Heating 








Transport Loss 
Storage to 
Space Heating 
















N.A. 








N.A. 














Space Heating 
Solar Energy Used 


























N.A. 


5.12 






Space Heating 
Subsystem 
Operating Energy 




Space Heating 
Auxiliary Thermal 
Used 






2.12 


25.78 










Space Heating 
Load 










(1) 




33.09 














Transport Lots 
Collector to 
Space Cooling 








Transport Loss 
Storage to 
Space Cooling 


















N.A. 








N.A. 














Space Cooling 
Solar Energy Used 


























N.A. 


N.A. 






Space Cooling 
Subsystem 
Operating Energy 




Space Cooling 
Auxiliary Thermal 
Used 










(1) 


N.A. 


N.A. 














Total Lots - 
Collector to 
Storage and Loads 






Space Cooling 
Load 




Total Lot* - 
Storage to Loads 


















* 


N.A. 


N.A. 





111 



• Denotes Unavailable Data 

N.A. denotes not applicable data 

(1) May contribute to offset of space heating Iped (if known - see text for discussion I 

5-6 



TABLE 5-3. SOLAR ENERGY DISTRIBUTION - SUMMARY - SEPTEMBER 1978 THROUGH MARCH 1979 

CHESTER WEST 

21.32 million Btu T0TAL $QLAR ENERGy COLLECTED 



100% 

* 



million Btu SQLAR ENERGY T0 L0ADS 



% 

* million Btu 



% 
5.12 million Btu 



24 % 
N.A. million Btu 



% 
* million Btu 



% 

* million Btu 



SOLAR ENERGY TO DHW SUBSYSTEM 

SOLAR ENERGY TO SPACE HEATING SUBSYSTEM 

SOLAR ENERGY TO SPACE COOLING SUBSYSTEM 
SOLAR ENERGY LOSSES 

SOLAR ENERGY LOSS FROM STORAGE 



* 

lion Btu SQLAR ENERGY L0SS IN TRANSPORT 



% 

* million Btu 

% 

N.A. million Btu 



% 

N.A. mi' 

% 

N.A. million Btu 



% 
N.A. million Btu 



% 
N.A. million Btu 



% 

N.A. mi' Btu 

% 

N.A. mi" ion Btu 



% 
N.A. million Btu 



0/ 

h 

.23 million Btu 



COLLECTOR TO STORAGE LOSS 
COLLECTOR TO LOAD LOSS 

COLLECTOR TO DHW LOSS 

COLLECTOR TO SPACE HEATING LOSS 

COLLECTOR TO SPACE COOLING LOSS 

: TO LOAD LOSS 

STORAGE TO DHW LOSS 

STORAGE TO SPACE HEATING LOSS 

STORAGE TO SPACE COOLING LOSS 



(±) 1 % 



SOLAR ENERGY STORAGE CHANGE (GAINS OR LOSSES) 



* - Denotes unavailable data 5-7 
N.A. - Denotes not applicable data 



The solar energy coefficient of performance (COP) is indicated in Table 5-4. 
The COP simply provides a numerical value for the relationship of solar 
energy collected or transported or used and the energy required to perform 
the transition. The greater the COP value, the more efficient the subsystem. 
The solar energy system at Chester West functioned at a weighted average COP 
value of 2.65 for the reporting period September 1978 through November 1978. 
System COPs were not computable for December through March. 

5.3 Subsystem Performance 

The Chester West solar energy installation may be divided into three subsys- 
tems: 

1. Collector Array and Storage 

2. Domestic Hot Water (DHW) 

3. Space Heating 

Each subsystem is evaluated and analyzed by the techniques defined in Section 
4 in order to produce the monthly performance reports. This section presents 
the results of integrating the monthly data available on the three subsystems 
for the period September 1978 through March 1979. 

5.3.1 Collector Array and Storage Subsystem 

5.3.1.1 Collector Array 

Collector array performance for the Chester West site is presented in Table 
5-5. The total incident solar radiation on the collector array for the 
period September 1978 through March 1979 was 57.50 million Btu. During the 
period the collector loop was operating the total insolation amounted to 
46.71 million Btu. The total collected solar energy for the period was 21.32 
million Btu, resulting in a collector array efficiency of 37 percent, based 
on total incident insolation. The average monthly solar energy delivered 
from the collector array to storage was 2.58 million Btu. Operating energy 
required by the collector loop was 1.67 million Btu. 



5-8 



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OPERATIONAL 
COLLECTOR ARRAY 
EFFICIENCY (%) 




<j co «t in lo in ^i- 


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OPERATIONAL 

INCIDENT ENERGY 

(Million Btu) 


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*3" CO i— i — O CO ■ — 

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SOLAR ENERGY 

(Million Btu) 


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12.99 
7.82 
8.01 
5.08 
5.46 
9.46 


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5-10 



Collector array efficiency has been computed from two bases. The first 
assumes that the efficiency is based upon all available solar energy. This 
approach makes the operation of the control system part of array efficiency. 
For example, energy may be available at the collector, but the collector 
fluid temperature is below the control minimum; therefore, the energy is not 
collected. In this approach, collector array performance is described by 
comparing the collected solar energy to the incident solar energy. The ratio 
of these two energies represents the collector array efficiency which may be 
expressed as 

"e = Vl 

where: n = collector array efficiency 

Q = collected solar energy 

Q. = incident solar energy 

The monthly efficiency computed by this method is listed in the column entitled 
"Collector Array Efficiency" in Table 5-5. 

The second approach assumes the efficiency is based upon the incident solar 
energy during the periods of collection only. 

Evaluating collector efficiency using operational incident energy and com- 
pensating for the difference between gross collector array area and the gross 
collector area yield operational collector efficiency. Operational collector 
efficiency, n co , is computed as follows: 

n co = Q s /(Q oi x £) 

a 

where: Q = collected solar energy 



Q . = operational incident energy 



5-11 



A = gross collector area (product of the number 
of collectors and the total envelope area of 
one unit) 

A = gross collector array area (total area perpen- 
a 

dicular to the solar flux vector, including all 
mounting, connecting and transport hardware 

A 
Note: The ratio j^- is typically 1.0 for most collector array configurations. 

a 

The monthly efficiency computed by this method is listed in the column entitled 
"Operational Collector Array Efficiency" in Table 5-5. This latter efficiency 
term is not the same as collector efficiency as represented by the ASHRAE 
Standard 93-77 [5]. Both operational collector efficiency and the ASHRAE 
collector efficiency are defined as the ratio of actual useful energy collected 
to solar energy incident upon the collector and both use the same definition 
of collector area. However, the ASHRAE efficiency is determined from instan- 
taneous evaluation under tightly controlled, steady-state test conditions, 
while the operational collector efficiency is determined from the actual 
conditions of daily solar energy system operation. Measured monthly values of 
operational incident energy and computed values of operational collector 
efficiency are presented in Table 5-5. 

5.3.1.2 Storage 

Storage performance data for the Chester West site for the reporting period 
is shown in Table 5-6. Results of analysis of solar energy losses during 
transport and storage are shown in Table 5-7. This table contains an evalua- 
tion of solar energy transport losses as a fraction of energy transported to 
subsystems. 

During the reporting period, the average monthly solar energy delivered to 
storage was 2.58 million Btu. On the average, 1.48 million Btu of solar 
energy was delivered from storage to the DHW and space heating subsystems. 



5-12 



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5-13 



TABLE 5-7. SOLAR ENERGY LOSSES - STORAGE AND TRANSPORT 

CHESTER WEST 







MONTH 




SEP 


OCT 


NOV 


DEC 


JAN 


FEB 


MAR 


TOTAL 


1. 


SOLAR ENERGY (SE) COLLECTED 
MINUS SE DIRECTLY TO LOADS 

(million Btu) 


3.46 


4.27 


1.85 


3.80 


1.99 


2.21 


3.74 


21.32 


2. 


SE TO STORAGE 
(million Btu) 


3.05 


3.50 


1.50 


3.52 


1.80 


2.08 


* 


15.45 


3. 


LOSS - COLLECTOR TO STORAGE (%) 
1 -2 


12 


18 


19 


7 


10 


6 


• 


— 


4. 


1 

CHANGE IN STORED ENERGY 
(million Btu) 


0.14 


0.12 


-0.39 


0.05 


0.00 


0.07 


0.24 


0.23 


5. 


SOLAR ENERGY - STORAGE TO 
DHW SUBSYSTEM (million Btu) 


0.75 


1.58 


0.51 


* 


• 


* 


• 


* 


6. 


SOLAR ENERGY - STORAGE TO 
SPACE HEATING SUBSYSTEM 

(million Btu) 


0.00 


0.39 


1.20 


1.17 


0.77 


0.86 


0.73 


5.12 


7. 


SOLAR ENERGY - STORAGE TO 




















SPACE COOLING SUBSYSTEM 


N.A. 


N.A. 


N.A. 


N.A. 


N.A. 


N.A. 


N.A. 


N.A. 




(million Btu) 


















8. 


LOSS FROM STORAGE (%) 
2 - (4 + 5+6 + 7) 
2 


71 


40 


12 


• 


* 


* 


• 


• 


9. 

■ 


HOT WATER SOLAR ENERGY (HWSE) 
FROM STORAGE (million Btu) 


0.75 


1.58 


0.51 


* 


* 


• 


* 


* 


10. 


LOSS - STORAGE TO HWSE (%) 
5-9 
5 


N.A. 


N.A. 


N.A. 


N.A. 


N.A. 


N.A. 


N.A. 


N.A. 


11. 


HEATING SOLAR ENERGY (HSE) 




















FROM STORAGE 


0.00 


0.39 


1.20 


1.17 


0.77 


0.86 


0.73 


5.12 




(million Btu) 


















12. 


LOSS - STORAGE TO HSE (%) 




















6 - 11 
6 


N.A. 


N.A. 


N.A. 


N.A. 


N.A. 


N.A. 


N.A. 


N.A. 



S002 



* - Denotes unavailable data 
N.A. - Denotes not applicable data 



5-14 



The storage eTficiency was 53 percent: This is calculated as the ratio of 
the sum of the energy removed from storage and the change in stored energy, 
to the energy delivered to storage. The average storage temperature for the 
period was 123°F. 

Storage subsystem performance is evaluated by comparison of energy to storage, 
energy from storage, and the change in stored energy. The ratio of the sum of 
energy from storage and the change in stored energy, to the energy to storage 
is defined as storage efficiency, r] . This relationship is expressed in the 
equation 

n s - (AQ ♦ Q so )/Q si 
where: 

aQ = change in stored energy. This is the difference in 
the estimated stored energy during the specified 
reporting period, as indicated by the relative 
temperature of the storage medium (either positive 
or negative value) 

Q = energy from storage. This is the amount of energy 
extracted by the load subsystem from the primary 
storage medium 

Q .= energy to storage. This is the amount of energy 

(both solar and auxiliary) delivered to the primary 
storage medium 

An effective storage heat transfer coefficient (C) for the storage subsystem 
can be defined as follows: 

c . (Q si -Q S0 -AQ s )/[T s - T a ) x t] !£ hr 



5-15 



where: 



C = effective storage heat transfer coefficient 

Q • = energy into storage 

Q = energy from storage 

AQ = change in stored energy 

T = storage average temperature 

T = average ambient temperature in the 
a 

vicinity of storage 

t = number of hours in the month 

5.3.2 Domestic Hot Water (DHW) Subsystem 

The DHW subsystem performance for the Chester West site for the reporting 
period is shown in Table 5-8. The DHW subsystem consumed a monthly average 
of 0.95^ ' million Btu of solar energy and 0.47 million Btu of auxiliary 
electrical energy to satisfy an average monthly hot water load of 0.46 million 
Btu. The average solar fraction of this load was 74^ ' percent. 

The performance of the DHW subsystem is described by comparing the amount of 
solar energy supplied to the subsystem with the total energy required by the 
subsystem. The total energy required by the subsystem consists of both solar 
energy and auxiliary thermal energy. The DHW load is defined as the amount 
of energy required to raise the mass of water delivered by the DHW subsystem 
between the temperature at which it entered the subsystem and its delivery 



* ' Weighted average based on 3-month data: September, October, and November 
(1978) 

5-16 



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5-17 



temperature. The DHW solar fraction is defined as the portion of the DHW 
load which is supported by solar energy. 

5.3.3 Space Heating Subsystem 

The space heating subsystem performance for the Chester West site for the 
reporting period is shown in Table 5-9. The space heating subsystem consumed 
5.12 million Btu of solar energy and 26.87 million Btu of auxiliary elec- 
trical energy to satisfy a space heating load of 33.09 million Btu. The 
solar fraction of this load was 15 percent. 

The performance of the space heating subsystem is described by comparing the 
amount of solar energy supplied to the subsystem with the energy required to 
satisfy the total space heating load. The energy required to satisfy the 
total load consists of both solar energy and auxiliary thermal energy. The 
ratio of solar energy supplied to the load to the total load is defined as 
the heating solar fraction. 

5.4 Operating Energy 

Measured values of the Chester West solar energy system and subsystem opera- 
ting energy for the reporting period are presented in Table 5-10. A total of 
5.27 million Btu of operating energy was consumed by the entire system during 
the reporting period. 

Operating energy for a solar energy system is defined as the amount of elec- 
trical energy required to support the subsystems without affecting their 
thermal state. 

Total system operating energy for Chester West is the energy required to 
support the energy collection and storage subsystem (ECCS), DHW subsystem, 
and space heating subsystem. With reference to the system schematic (Figure 
3-1), the ECCS operating energy includes pump PI, EP100. The DHW subsystem 
operating energy consists of pump P2, EP300. The space heating subsystem 
operating energy consists of pump P3, EP400, Fan B,EP401, and the heat pump 
fan power. 

5-18 



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TOTAL SYSTEM 

OPERATING ENERGY 

(Million Btu) 


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OPERATING ENERGY 

(Million Btu) 


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SPACE HEATING 

OPERATING ENERGY 

(Million Btu) 


0.00 
0.01 
0.13 
0.51 
0.80 
0.49 
0.18 


CM 
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DOMESTIC HOT WATER 

OPERATING ENERGY 

(Million Btu) 


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(Million Btu) 


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5-20 



5.5 Energy Savings 

Energy savings for the Chester West site for the reporting period are presented 
in Table 5-11. For this period the monthly average savings on electrical 
energy were 0.93^ ' million Btu. An electrical energy expense of 3.31 mil- 
lion Btu was incurred during the reporting period for the operation of solar 
energy transportation pumps. 

Solar energy system savings are realized whenever energy provided by the 
solar energy system is used to meet system demands which would otherwise be 
met by auxiliary energy sources. The operating energy required to provide 
solar energy to the load subsystems is subtracted from the solar energy 
contribution to determine net savings. 

The auxiliary source at Chester West consists of a DHW heater (EP301), a heat 
pump (EP403), and electrical strip heaters (EP402). These units are con- 
sidered to be 70 percent efficient for computational purposes. 



* ' Weighted average based on 3-month data: September, October and November 
(1978) 

5-21 



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5-22 



6. REFERENCES 

1. U.S. Department of Energy, National Solar Data Network , prepared 
under contract number EG-77-C-4049 by IBM Corporation, 
December 1977. 

2. J. T. Smok, V. S. Sohoni , J. M. Nash, "Processing of Instrumented 
Data for the National Solar Heating and Cooling Demonstration 
Program," Conference on Performance Monitoring Techniques for 
Evaluation of Solar Heating and Cooling Systems, Washington, D.C., 
April 1978. 

3. E. Streed, et. al . , Thermal Data Requirements and Performance 
Evaluation Procedures for the National Solar Heating and Cooling 
Demonstration Program , NBSIR-76-1137, National Bureau of Standards, 
Washington, D.C., 1976. 

4. Mears, J. C. Referen ce Monthly Environmental Data for Systems in 
the National Solar Data Network . Department of Energy report 
SOLAR/0019-79/36. Washington, D.C., 1979. 

5. ASHRAE Standard 93-77 , Methods of Testing to Determine the Thermal 
Performance of Solar Collectors , The American Society of Heating, 
Refrigeration and Air Conditioning Engineers, Inc., New York, N.Y., 
1977. 

6.# Monthly Performance Report , Chester West , SOLAR/1030-78/09, Department 
of Energy, Washington, D.C. , (September 1978). 

7.# Monthly Performance Report , Chester West , SOLAR/ 1030- 78/ 10, Department 
of Energy, Washington, D.C. , (October 1978). 

8.# Monthly Performance Report , Che ster West , SOLAR/1030-78/11, Department 
of Energy, Washington, D.C, (November 1978). 

9.# Monthly Performance Report , Chester West , SOLAR/1030-78/12, Department 
of Energy, Washington, D.C. , (December 1978). 

10. # Monthly Performance Report , Chester West , SOLAR/1030-79/01 , Department 
of Energy, Washington, D.C, (January 1979). 

11. # Monthly Performance Report , Chester West , SOLAR/1030-79/02, Department 
of Energy, Washington, D.C. , (February 1979). 

12. # Monthly Performance Report , Chester West , SOLAR/1030-79/03, Department 
of Energy, Washington, D.C , (March 1979). 



# Copies of these reports may be obtained from Technical Information 
Center, P. 0. Box 62, Oak Ridge, Tennessee 37830. 

6-1 






APPENDIX A 
DEFINITIONS OF PERFORMANCE FACTORS AND SOLAR TERMS 



COLLECTOR ARRAY PERFORMANCE 

The collector array performance is characterized by the amount of solar 
energy collected with respect to the energy available to be collected. 

o INCIDENT SOLAR ENERGY (SEA) is the total insolation available 
on the gross collector array area. This is the area of the 
collector array energy- receiving aperture, including the 
framework which is an integral part of the collector structure. 

o OPERATIONAL INCIDENT ENERGY (SEOP) is the amount of solar energy 
incident on the collector array during the time that the col- 
lector loop is active (attempting to collect energy). 

o COLLECTED SOLAR ENERGY (SECA) is the thermal energy removed 
from the collector array by the energy transport medium. 

o COLLECTOR ARRAY EFFICIENCY (CAREF) is the ratio of the energy 
collected to the total solar energy incident on the collector 
array. It should be emphasized that this efficiency factor is 
for the collector array, and available energy includes the 
energy incident on the array when the collector loop is inac- 
tive. This efficiency must not be confused with the more 
common collector efficiency figures which are determined from 
instantaneous test data obtained during steady-state operation 
of a single collector unit. These efficiency figures are often 
provided by collector manufacturers or presented in technical 
journals to characterize the functional capability of a partic- 
ular collector design. In general, the collector panel maximum 
efficiency factor will be significantly higher than the col- 
lector array efficiency reported here. 

STORAGE PERFORMANCE 

The storage performance is characterized by the relationships among the 
energy delivered to storage, removed from storage, and the subsequent 
change in the amount of stored energy. 

o ENERGY TO STORAGE (STEI) is the amount of energy, both solar 
and auxiliary, delivered to the primary storage medium. 

o ENERGY FROM STORAGE (STEO) is the amount of energy extracted 
by the load subsystems from the primary storage medium. 



A-l 



o CHANGE IN STORED ENERGY (STECH) is the difference in the estimated 
stored energy during the specified reporting period, as indicated 
by the relative temperature of the storage medium (either posi- 
tive or negative value). 

o STORAGE AVERAGE TEMPERATURE (TST) is the mass-weighted average 
temperature of the primary storage medium. 

o STORAGE EFFICIENCY (STEFF) is the ratio of the sum of the energy 
removed from storage and the change in stored energy to the 
energy delivered to storage. 

ENERGY COLLECTION AND STORAGE SUBSYSTEM 

The Energy Collection and Storage Subsystem (ECSS) is composed of the 
collector array, the primary storage medium, the transport loops between 
these, and other components in the system design which are necessary to 
mechanize the collector and storage equipment. 

o INCIDENT SOLAR ENERGY (SEA) is the total insolation available 
on the gross collector array area. This is the area of the 
collector array energy- receiving aperture, including the frame- 
work which is an integral part of the collector structure. 

o AMBIENT TEMPERATURE (TA) is the average temperature of the out- 
door environment at the site. 

o ENERGY TO LOADS (SEL) is the total thermal energy transported 
from the ECSS to all load subsystems. 

o AUXILIARY THERMAL ENERGY TO ECSS (CSAUX) is the total auxiliary 
energy supplied to the ECSS, including auxiliary energy added to 
the storage tank, heating devices on the collectors for freeze- 
protection, etc. 

o ECSS OPERATING ENERGY (CSOPE) is the critical operating energy 
required to support the ECSS heat transfer loops. 

HOT WATER SUBSYSTEM 

The hot water subsystem is characterized by a complete accounting of the 
energy flow into and from the subsystem, as well as an accounting of 
internal energy. The energy into the subsystem is composed of auxiliary 
fossil fuel, and electrical auxiliary thermal energy, and the operating 
energy for the subsystem. 

o HOT WATER LOAD (HWL) is the amount of energy required to heat 
the amount of hot water demanded at the site from the incoming 
temperature to the desired outlet temperature. 



A-2 






o SOLAR FRACTION OF LOAD (HWSFR) is the percentage of the load 
demand which is supported by solar energy. 

o SOLAR ENERGY USED (HWSE) is the amount of solar energy supplied 
to the hot water subsystem. 

o OPERATING ENERGY (MOPE) is the amount of electrical energy 
required to support the subsystem, (e.g., fans, pumps, etc.) 
and which is not intended to directly affect the thermal state 
of the subsystem. 

o AUXILIARY THERMAL USED (HWAT) is the amount of energy supplied 
to the major components of the subsystem in the form of thermal 
energy in a heat transfer fluid, or its equivalent. This term 
also includes the converted electrical and fossil fuel energy 
supplied to the subsystem. 

o AUXILIARY FOSSIL FUEL (HWAF) is the amount of fossil fuel energy 
supplied directly to the subsystem. 

o ELECTRICAL ENERGY SAVINGS (HWSVE) is the estimated difference 
between the electrical energy requirements of an alternative 
conventional system (carrying the full load) and the actual 
electrical energy required by the subsystem. 

- o FOSSIL FUEL SAVINGS (HWSVF) is the estimated difference between 
the fossil fuel energy requirements of the alternative conven- 
tional system (carrying the full load) and the actual fossil 
fuel energy requirements of the subsystem. 

SPACE HEATING SUBSYSTEM 

The space heating subsystem is characterized by performance factors account- 
ing for the complete energy flow into the subsystem. The average building 
temperature is tabulated to indicate the relative performance of the 
subsystem in satisfying the space heating load and in controlling the tem- 
perature of the conditioned space. 

o SPACE HEATING LOAD (HL) is the sensible energy added to the 
air in the building. 

o SOLAR FRACTION OF LOAD (HSFR) is the fraction of the sensible 
energy added to the air in the building derived from the solar 
energy system. 

o SOLAR ENERGY USED (HSE) is the amount of solar energy supplied 
to the space heating subsystem. 



A-3 



OPERATING ENERGY (HOPE) is the amount of electrical energy 
required to support the subsystem, (e.g., fans, pumps, etc.) 
and which is not intended to directly affect the thermal state 
of the system. 

AUXILIARY THERMAL USED (HAT) is the amount of energy supplied 
to the major components of the subsystem in the form of thermal 
energy in a heat transfer fluid or its equivalent. This term 
also includes the converted electrical and fossil fuel energy 
supplied to the subsystem. 

AUXILIARY ELECTRICAL FUEL (HAE) is the amount of electrical 
energy supplied directly to the subsystem. 

ELECTRICAL ENERGY SAVINGS (HSVE) is the estimated difference 
between the electrical energy requirements of an alternative 
conventional system (carrying the full load) and the actual 
electrical energy required by the subsystem. 

BUILDING TEMPERATURE (TB) is the average heated space dry bulb 
temperature. 



A-4 



APPENDIX B 
SOLAR ENERGY SYSTEM PERFORMANCE EQUATIONS 
CHESTER WEST 



INTRODUCTION 

Solar energy system performance is evaluated by performing energy balance 
calculations on the system and its major subsystems. These calculations 
are based on physical measurement data taken from each sensor every 
320 seconds. This data is then mathematically combined to determine the 
hourly, daily, and monthly performance of the system. This appendix 
describes the general computational methods and the specific energy 
balance equations used for this site. 

Data samples from the system measurements are integrated to provide 
discrete approximations of the continuous functions which characterize 
the system's dynamic behavior. This integration is performed by summation 
of the product of the measured rate of the appropriate performance para- 
meters and the sampling interval over the total time period of interest. 

There are several general forms of integration equations which are 
applied to each site. These general forms are exemplified as follows: 
The total solar energy available to the collector array is given by 

SOLAR ENERGY AVAILABLE = (1/60) E [1001 x AREA] x Ax 

where 1001 is the solar radiation measurement provided by the pyranometer 
in Btu per square foot per hour, AREA is the area of the collector array 
in square feet, Ax is the sampling interval in minutes, and the factor 
(1/60) is included to correct the solar radiation "rate" to the proper 
units of time. 

Similarly, the energy flow within a system is given typically by 

COLLECTED SOLAR ENERGY = Z [Ml 00 x AH] x Ax 

where Ml 00 is the mass flow rate of the heat transfer fluid in lb /min and 
AH is the enthalpy change, in Btu/lb , of the fluid as it passes through 
the heat exchanging component. 

For a liquid system AH is generally given by 

AH = C AT 
P 

where C" is the average specific heat, in Btu/(lb -°F), of the heat trans- 
fer fluid and AT, in °F, is the temperature differential across the heat 
exchanging component. 



B-l 



For an air system AH is generally given by 

AH = H (T .) - H (T. ) 
a v out 7 a v in' 

where H (T) is the enthalpy, in Btu/lb , of the transport air evaluated 
at the inlet and outlet temperatures or the heat exchanging component. 

H (T) can have various forms, depending on whether or not the humidity 
ratio of the transport air remains constant as it passes through the heat 
exchanging component. 

For electrical power, a general example is 

ECSS OPERATING ENERGY = (3413/60) I [EP100] x Ax 

where EP100 is the power required by electrical equipment in kilowatts 
and the two factors (1/60) and 3413 correct the data to Btu/min. 

These equations are comparable to those specified in "Thermal Data 
Requirements and Performance Evaluation Procedures for the National Solar 
Heating and Cooling Demonstration Program." This document was prepared 
by an interagency committee of the Government, and presents guidelines 
for thermal performance evaluation. 

Performance factors are computed for each hour of the day. Each integra- 
tion process, therfore, is performed over a period of one hour. Since 
long-term performance data is desired, it is necessary to build these 
hourly performance factors to daily values. This is accomplished, for 
energy parameters, by summing the 24 hourly values. For temperatures, 
the hourly values are averaged. Certain special factors, such as effi- 
ciencies, require appropriate handling to properly weight each hourly 
sample for the daily value computation. Similar procedures are required 
to convert daily values to monthly values. 



B-2 






EQUATIONS USED TO GENERATE MONTHLY PERFORMANCE VALUES 

NOTE: SENSOR IDENTIFICATION (MEASUREMENT) NUMBERS REFERENCE SYSTEM 
SCHEMATIC FIGURE 3-1 



AVERAGE AMBIENT TEMPERATURE (°F) 

TA = (1/60) x E T001 x At 
AVERAGE BUILDING TEMPERATURE (°F) 

. TB = (1/60) x T600 x Ax 
DAYTIME AVERAGE AMBIENT TEMPERATURE (°F) 

TDA = (1/360) x E T001 x Ax 

FOR + 3 HOURS FROM SOLAR NOON 
HOT WATER LOAD (BTU) 

HWL = E [M301 * HWD (T351.T301)] * Ax 
SOLAR ENERGY TO DHW TANK (BTU) 

HWSE = E [M300 * HWD (T300,T350)] * Ax 
INCIDENT SOLAR ENERGY PER SQUARE FOOT (BTU/FT 2 ) 

SE = (1/60) x E 1001 x Ax 
INCIDENT SOLAR ENERGY ON COLLECTOR ARRAY (BTU) 

SEA = (1/60) x E [1001 x CLAREA] x Ax 
OPERATIONAL INCIDENT SOLAR ENERGY (BTU) 

SEOP = (1/60) x E [1001 x CLAREA] x Ax 
WHEN THE COLLECTOR LOOP IS ACTIVE 
SOLAR ENERGY COLLECTED BY THE ARRAY (BTU) 

SECA = E [M100 * CPC(T100 + T150)/2 * (T150 - T100)] * Ax 
SOLAR ENERGY TO STORAGE 

STEI = E [Ml 00 . * CP61 ((Tlol + T151/2) * (T101 - T151)] * Ax 



B-3 



ENERGY FROM STORAGE TO DHW LOAD (BTU) 

STE02 = l [M300 * HWD CT300.T350) * At 
ENERGY FROM STORAGE TO SPACE HEATING LOAD (BTU) 

STEOl = E [M400 * HWD (T400,T450) * At 
ENERGY FROM STORAGE TO SPACE HEATING LOAD (BTU) DEFAULT 

STEOIAIR = E [M401 * HRF * (T451 - T401)] * At 

USED IN PLACE OF STEOl WHEN W400 PROVIDED INVALID DATA 
ENERGY FROM STORAGE (BTU) 

STEO = STEOl + STE02 
AVERAGE TEMPERATURE OF STORAGE 

TST = (1/60) x S [(T200 + T201 + T202)/3] x At 
ECSS OPERATING ENERGY (BTU) 

CSOPE = 56.86833 x I EP100 x At 
HOT WATER CONSUMED (GALLONS) 

HWCSM = I W301 x At 
HOT WATER SUBSYSTEM OPERATING ENERGY (BTU) 

HWOPE = 56.86833 x I EP300 x At 
HOT WATER AUXILIARY ELECTRIC ENERGY (BTU) 

HWAE = 56.86833 x £ EP301 x At 
SPACE HEATING OPERATING ENERGY, SOLAR AND BLOWER (BTU) 

HOPEX = Z [56.86833 * (EP400 + EP401)] * At 
WHEN IN HEATING MODE (T453 - T401 ) > 1 
HEAT PUMP FAN ELECTRICAL (BTU) 

FP = 0.5 * I At 

WHEN (T452 - T451 ) > 1 AND EP403 > 
SPACE HEATING OPERATING ENERGY, SOLAR, BLOWER AND HEAT PUMP FAN (BTU) 

HOPE = HOPEX + FP 

WHEN (T452 - T451 ) > 1 AND EP403 > 

B-4 



SPACE HEATING, HEAT PUMP (BTU) 

HAE1 = 56.86833 * E (EP403 - FP) * At 

WHEN (T452 - T451 ) > 1 AND EP403 > 
SPACE HEATING, HEAT STRIPS (BTU) 

HAE2 - 56.86833 * E EP402 * At 
SPACE HEATING, AUXILIARY ELECTRICAL ENERGY (BTU) 

HAE = HAE1 + HAE2 
SPACE HEATING, OPERATING ENERGY, SOLAR POWER 

HOPE1 = 56.86833 * E EP400 * At 
SERVICE HOT WATER TEMPERATURE (°F) 

THW = (1/60) * (T351 * M301 )/M301 ) * At 
WHEN WATER IS BEING DRAWN 
SERVICE SUPPLY WATER TEMPERATURE (°F) 

TSW = (1/60) * (T301 * M301) * At 
WHEN WATER IS BEING DRAWN 
SPACE HEATING AUXILIARY THERMAL ENERGY (BTU) 

HAT = 0.7 * HAE1 + HAE2 
COLLECTED SOLAR ENERGY (BTU) 

SEC = SECA/CLAREA 
ENERGY TO STORAGE (BTU) 

STEI + E M100 * CP61 ((T101 + T151)/2) * (T101 - Tl 51 ) * At 
CHANGE IN STORED ENERGY (BTU) 

STECH - STOCAP * (RHOTSTL * CPTSTL * TSTL - RHOTSTLP * CPTSTLP * TSTLP) 
STOCAP EQUALS STORAGE CAPACITY. TSTL IS THE LATEST TST AND TSTLP 
IS THE TST JUST PREVIOUS. 



B-5 



ENERGY DELIVERED TO LOAD SUBSYSTEMS FROM ECSS (BTU) 

CSEO = STEO 
STORING EFFICIENCY 

STEFF = (STECH + STEO)/STEI 
ECSS SOLAR CONVERSION EFFICIENCY 

CSCEF = CSEO/SEA 
HOT WATER AUXILIARY THERMAL ENERGY (BTU) 

HWAT = HWAE 
HOT WATER SOLAR FRACTION 

HWSFR = FRACTION OF DELIVERED HOT WATER LOAD DERIVED FROM SOLAR 
SOURCES AFTER PRO-RATING STORAGE LOSSES TO SOLAR AND 
AUXILIARY SOURCES 
HOT WATER ELECTRICAL ENERGY SAVINGS (BTU) 

HWSVE = HWSE - HWOPE 
SOLAR ENERGY TO SPACE HEATING (BTU) 

HSE = STEOl 
SPACE HEATING LOAD, HEAT PUMP (BTU) 

HLHP = E M401 * HRF * (T452 - T451 ) * At 
WHEN (T452 - T451 ) > 1 AND EP403 > 
SPACE HEATING LOAD (BTU) 

HL = HLHP + HAE2 + HSE 
SPACE HEATING SYSTEM ELECTRICAL ENERGY SAVINGS (BTU) 

HSVE = (HSE/HPFRAC * HPCOPH + (1 - HPFRAC))) - HOPE1 
SYSTEM LOAD 

SYSL = HL + HWL 



B-6 



SOLAR ENERGY TO LOAD 

SEL = STEO 
SPACE HEATING SOLAR FRACTION 

HSFR = 100 x (HSE/HL) 
SOLAR FRACTION OF SYSTEM LOAD 

SFR = (HL x HSFR + HWL x HWSFR)/SYSL 
AUXILIARY THERMAL ENERGY TO LOADS 

AXT = HWAT + HAT 
AUXILIARY ELECTRICAL ENERGY TO LOADS 

AXE = HAE + HWAE 
SYSTEM OPERATING ENERGY 

SYSOPE = HWOPE + HOPE + CSOPE 
TOTAL ENERGY CONSUMED 

TECSM = SYSOPE + AXE + SECA 
TOTAL ELECTRICAL ENERGY SAVINGS 

TSVE = HWSVE + HSVE - CSOPE 
SYSTEM PERFORMANCE FACTOR 

SYSPF = SYSL/((AXE + SYSOPE) x 3.33) 



B-7 



APPENDIX C 
LONG-TERM AVERAGE WEATHER CONDITIONS 



This appendix contains a table which lists the long-term average weather 
conditions for each month of the year for this site. 






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C-2 



APPENDIX D 
MONTHLY SOLAR ENERGY DISTRIBUTION FLOWCHARTS 






The flowcharts in this appendix depict the quantity of solar energy corre- 
sponding to each major component or characteristic of the Chester West solar 
energy system for 7 months of the reporting period. Each monthly flowchart 
represents a solar energy balance as the total input equals the total output 



D-l 



FIGURE D-l.. 



SOLAR ENERGY (MILLION BTU) DISTRIBUTION FLOWCHART 

CHESTER WEST 



SEPTEMBER 1978 



incident 
Solar Energy 








■ 

Solar Energy 
Storage Losses 


8.68 






2.16 




i 






(i) 






Change in 
Stored Energy 






Operational 




Transport Loss 
Collector to 
Storage 


ECSS Subsystem 
Operating Energy 






Incident 
Solar Energy 






0.14 




| 7.46 






0.41 


0.27 




1 




1 
















i 
1 

1 




! 

Collected 
Solar Energy 








Solar Energy 
to Storage 


Solar Energy 
from Storage 










id 


3.46 






m 


3.05 






0.75 








Transport Loss 
Collector to DHW 








Transport Loss 
Storage to DHW 


















N.A. 








N.A. 














Domestic Hot 
Water Solar 
Energy Used 
















(i) 










N.A. 


0.75 






DHW Subsystem 
Operating Energy 




Domestic Hot 
Water Auxiliary 
Thermal Used 






0.33 


0.04 










Domestic Hot 
Water Load 










(it 




0.23 












Transport Loss 
Collector to 
Space Heating 








Transport Loss 
Storage to 
Space Heating 
















N.A. 








N.A. 














Space Heating 
Solar Energy Used 


























N.A. 


0.0 






Space Heating 
Subsystem 
Operating Energy 




Space Heating 
Auxiliary Thermal 
Used 






0.0 


0.0 










Space Heating 
Load 










(i) 




Q.O 












Transport Loss 
Collector to 
Space Cooling 








Transport Loss 
Storage to 
Space Cooling 
















N.A. 








N.A. 














Space Cooling 
Solar Energy Used 


























N.A. 


N.A. 






Space Cooling 
Subsystem 
Operating Energy 




Space Cooling 
Auxiliary Thermal 
Used 










in 


N.A. 


N.A. 












Total Loss - 
Collector to 
Storage and Loads 






Space Cooling 
Load 




Total Loss - 
Storage to Loads 


















0.41 


N.A. 


N.A. 





(II 



* Denotes Unavailable Data 

N.A. denotes not applicable data 

(1) May contribute to offset of space heating load (if known - see text for discussion) 

D-2 



sooz 



FIGURE D-2. 



SOLAR ENERGY (MILLION BTU) DISTRIBUTION FLOWCHART - OCTOBER 1978 

CHESTER WEST 



Incident 
Solar Energy 






Solar Energy 
Storage Losses 


12.99 








1.41 


1 


i 






in 






Change in 
Stored Energy 








Operational 
Incident 
Solar Energy 




Transport Loss 
Collector to 
Storage 


ECSS Subsystem 
Operating Energy 












0.12 




11.37 






0.77 


0.32 




♦ 






1 
















i 
1 






Collected 
Solar Energy 








Solar Energy 
to Storage 


i 


Solar Energy 
from Storage 










4.27 






ID 


3.50 






d) 


1.97 








Transport Loss 
Collector to DHW 








Transport Loss 
Storage to DHW 


















N.A. 








N.A. 














Domestic Hot 
Water Solar 
Energy Used 


























N.A. 


1.58 






DHW Subsystem 
Operating Energy 




Domestic Hot 

Water Auxiliary 
Thermal Used 






0.41 


0.0 










Domestic Hot 
Water Load 










(1) 




0.23 






d) 








Transport Loss 
Collector to 
Space Heating 








Transport Loss 
Storage to 
Space Heating 
















N.A. 








N.A. 














Space Heating 
Solar Energy Used 


























N.A. 


0.39 






Space Heating 
Subsystem 
Operating Energy 




Space Heating 
Auxiliary Thermal 
Used 






0.01 


0.03 










Space Heating 
Load 










(1) 




Q.45 














Transport Loss 
Collector to 
Space Cooling 








Transport Loss 
Storage to 
Space Cooling 


















N.A. 








N.A. 














Space Cooling 
Solar Energy Used 


























N.A. 


N.A. 






Space Cooling 
Subsystem 
Operating Energy 




Space Cooling 
Auxiliary Thermal 
Used 










(1) 


N.A. 


N.A. 














Total Loss - 
Collector to 
Storage and Loads 






Space Cooling 
Load 




Total Loss - 
Storage to Loads 


















0.77 


N.A. 


N.A. 





(11 



* Denotes Unavailable Data 

N.A. denotes not applicable data 

(1) May contribute to offset of space heating load (if known - see text for discussion) 

D-3 



S002 



riciimt u-j. 



bULMK tNtKGY (MILLION BTU) DISTRIBUTION FLOWCHART 

CHESTER WEST 



NOVEMBER 1978 



1 

Incident 
Solar Energy 






Solar Energy 
Storage Losses 


7.82 








0.1 


8 




i 












Change in 
Stored Energy 








Operational 
Incident 
Solar Energy 




Transport Loss 
Collector to 
Storage 




ECSS Subsystem 
Operating Energy 








-0.39 




4.18 






0.35 


0.41 




♦ 






1 
















i 
1 






Collected 
Solar Energy 








Solar Energy 
to Storage 


1 


Solar Energy 
from Storage 










1.85 






in 


1.50 








1.71 








Transport Loss 
Collector to DHW 








Transport Loss 
Storage to DHW 


















N.A. 








N.A. 














Domestic Hot 
Water Solar 
Energy Used 


























N.A. 


0.51 






OHW Subsystem 
Operating Energy 




Domestic Hot 
Water Auxiliary 
Thermal Used 






0.18 


0.46 










Domestic Hot 
Water Load 










in 




0.44 






id 








Transport Loss 
Collector to 
Space Heating 








Transport Loss 
Storage to 
Space Heating 
















N.A. 








N.A. 














Space Heating 
Solar Energy Used 


























N.A. 


1.20 






Space Heating 
Subsystem 
Operating Energy 




Space Heating 
Auxiliary Thermal 
Used 






0.13 


0.86 










Space Heating 
Load 










id 




2.37 














Transport Loss 
Collector to 
Space Cooling 








Transport Loss 
Storage to 
Space Cooling 


















N.A. 








N.A. 














Space Cooling 
Solar Energy Used 


























N.A. 


N.A. 






Space Cooling 
Subsystem 
Operating Energy 




Space Cooling 
Auxiliary Thermal 
Used 












N.A. 


N.A. 














Total Loss - 
Collector to 
Storage and Loads 


HI 






Space Cooling 
Load 




Total Loss - 
Storage to Loads 








* 










0.35 


N.A. 


N.A. 





(II 



• Denotes Unavailable Data 

N.A. denotes not applicable data 

(1) May contribute to offset of spacs heating Ipad (if known - see text for discussion) 

D-4 



FIGURE D-4. SOLAR ENERGY (MILLION BTU) DISTRIBUTION FLOWCHART - DECEMBER 1978 

CHESTER WEST 






Incident 
Solar Energy 






Solar Energy 
Storage Losses 


8.01 








• 


' 


■ 






(D 






Change in 
Stored Energy 




I 


Operational 
Incident 
Solar Energy 




Transport Loss 
Collector to 
Storage 


ECSS Subsystem 
Operating Energy 












0.05 




7.15 






0.28 


0.22 




♦ 






1 
















i 
1 






Collected 
Solar Energy 








Solar Energy 
to Storage 


i 


Solar Energy 
from Storage 










3.80 






in 


3.52 








* 








Transport Loss 
Collector to DHW 








Transport Loss 
Storage to DHW 


















N.A. 








N.A. 














Domestic Hot 
Water Solar 
Energy Used 


























N.A. 


* 






DHW Subsystem 
Operating Energy 




Domestic Hot 
Water Auxiliary 
Thermal Used 






0.18 


0.46 










Domestic Hot 
Water Load 










ID 




* 






id 








Transport Loss 
Collector to 
Space Heating 








Transport Loss 
Storage to 
Space Heating 
















N.A. 








N.A. 














Space Heating 
Solar Energy Used 


























N.A. 


1.17 






Space Heating 
Subsystem 
Operating Energy 




Space Heating 
Auxiliary Thermal 
Used 






0.51 


4.98 










Space Heating 
Load 










ID 




6.05 














Transport Loss 
Collector to 
Space Cooling 








Transport Loss 
Storage to 
Space Cooling 


















N.A. 








N.A. 














Space Cooling 
Solar Energy Used 
























N.A. 


N.A. 






Space Cooling 
Subsystem 
Operating Energy 




Space Cooling 
Auxiliary Thermal 
Used 










(1) 


N.A. 


N.A. 














Total Loss - 
Collector to 
Storage and Loads 






Space Cooling 
Load 




Total Loss - 
Storage to Loads 


















0.28 


N.A. 


N.A. 





* Denotes Unavailable Data 

N.A. denotes not applicable data 

(1) May contribute to offset of space heating load (if known - see text for discussion) 

D-5 



S002 



FIGURE D-5. SOLAR ENERGY (MILLION BTU) DISTRIBUTION FLOWCHART - JANUARY 1979 

CHESTER WEST 



Incident 
Solar Energy 








Solar Energy 
Storage Losses 


5.08 






* 




i 






id 






Change in 
Stored Energy 


i 




Operational 
Incident 
Solar Energy 




Transport Loss 
Collector to 
Storage 


ECSS Subsystem 
Operating Energy 










0.0 










4.01 


0.19 


0.16 




♦ 






















i 
1 

1 




Collected 
Solar Energy 








Solar Energy 
to Storage 


Solar Energy 
from Storage 










(D 


1.99 






id 


1.80 






* 








Transport Loss 
Collector to OHW 








Transport Loss 
Storage to DHW 


















N.A. 








N.A. 














Domestic Hot 
Water Solar 
Energy Used 
















id 










N.A. 


* 






DHW Subsystem 
Operating Eneigy 




Domestic Hot 
Water Auxiliary 
Thermal Used 






0.12 


0.66 










Domestic Hot 
Water Load 










(i) 




0.39 












Transport Loss 
Collector to 
Space Heating 








Transport Loss 
Storage to 
Space Heating 














N.A. 








N.A. 














Space Heating 
Solar Energy Used 


























N.A. 


0.77 






Space Heating 
Subsystem 
Operating Energy 




Space Heating 
Auxiliary Thermal 
Used 






0.80 


10.81 










Space Heating 
Load 










(i) 




13.39 












Transport Loss 
Collector to 
Space Cooling 








Transport Loss 
Storage to 
Space Cooling 
















N.A. 








N.A. 














Space Cooling 
Solar Energy Used 










■ 
















N.A. 


N.A. 






Space Cooling 
Subsystem 
Operating Energy 




Space Cooling 
Auxiliary Thermal 
Used 










id 


N.A. 


N.A. 












Total Loss - 
Collector to 
Storage and Loads 






Space Cooling 
Load 




Total Loss - 
Storage to Loads 


















0.19 


N.A. 


N.A. 





(1) 



* Denotes Unavailable Data 

N.A. denotes not applicable data 

(1) May contribute to offset of space heating Ipad (if known - see text for discussion) 

D-6 



FIGURE D-6. SOLAR ENERGY (MILLION BTU) DISTRIBUTION FLOWCHART - FEBRUARY 1979 

CHESTER WEST 



Incident 
Solar Energy 






Solar Energy 
Storage Losses 


5.46 








* 




• 






in 






Change in 
Stored Energy 






Operational 
Incident 
Solar Energy 




Transport Loss 
Collector to 
Storage 


ECSS Subsystem 
Operating Energy 












0.07 




4.37 






0.13 


0.16 




♦ 








• 
















i 
1 






Collected 
Solar Energy 








Solar Energy 
to Storage 


i 


Solar Energy 
from Storage 










2.21 






in 


2.08 






in 


* 








Transport Loss 
Collector to DHW 








Transport Loss 
Storage to DHW 


















N.A. 








N.A. 














Domestic Hot 
Water Solar 
Energy Used 


























N.A. 


* 






DHW Subsystem 
Operating Energy 




Domestic Hot 
Water Auxiliary 
Thermal Used 






0.17 


0.52 










Domestic Hot 
Water Load 










id 




0.33 






in 








Transport Loss 
Collector to 
Space Heating 








Transport Loss 
Storage to 
Space Heating 
















N.A. 








N.A. 














Space Heating 
Solar Energy Used 


























N.A. 


0.86 






Space Heating 
Subsystem 
Operating Energy 




Space Heating 
Auxiliary Thermal 
Used 






0.49 


7.88 










Space Heating 
Load 










id 




8.63 














Transport Loss 
Collector to 
Space Cooling 








Transport Loss 
Storage to 
Space Cooling 


















N.A. 








N.A. 














Space Cooling 
Solar Energy Used 


























N.A. 


N.A. 






Space Cooling 
Subsystem 
Operating Energy 




Space Cooling 
Auxiliary Thermal 
Used 










id 


N.A. 


N.A. 














Total Loss - 
Collector to 
Storage and Loads 






Space Cooling 
Load 




Total Loss - 
Storage to Loads 


















0.13 


N.A. 


N.A. 





(II 



* Denotes Unavailable Data 

N.A. denotes not applicable data 

(1) May contribute to offset of space heating Ipad (if known - see text for discussion) 

D-7 



FIGURE D-7. SOLAR ENERGY (MILLION BTU) DISTRIBUTION FLOWCHART 

CHESTER WEST 



MARCH 1979 



.ilent 
Solw Energy 






Solar Energy 
Storage Losses 


9.46 








* 


1 


1 






(1) 






Change in 
Stored Energy 






Operational 
Incident 
Solar Energy 




Transport Loss 
Collector to 
Storage 


ECSS Subsystem 
Operating Energy 












0.24 










8.17 


* 


0.40 




♦ 
























i 
1 






ollected 
iolai Energy 








Solar Energy 
to Storage 


i 


Solar Energy 
from Storage 










3.74 






111 


• 








* 








Transport Lois 
Collector to DHW 








Transport Loss 
Storage to DHW 


















N.A. 








N.A. 














Domestic Hot 
Water Solar 
Energy Used 


























N.A. 


* 






DHW Subsystem 
Operating Energy 




Domestic Hot 
Water Auxiliary 
Thermal Used 






0.09 


1.15 










Domestic Hot 
Water Load 










(1) 




1.11 






id 








Transport Loss 
Collector to 
Space Heating 








Transport Loss 
Storage to 
Space Heating 
















N.A. 








N.A. 














Space Heating 
Solar Energy Used 


























N.A. 


0.73 






Space Heating 
Subsystem 
Operating Energy 




Space Heating 
Auxiliary Thermal 
Used 






0.18 


1.22 










Space Heating 
Load 










(1) 




2.20 














Transport Loss 
Collector to 
Space Cooling 








Transport I oss 
Storage to 
Space Cooling 


















N.A. 








N.A. 














Space Cooling 
Solar Energy Used 


























N.A. 


N.A. 






Space Cooling 
Subsystem 
Operating Energy 




Space Cooling 
Auxiliary Thermal 
Used 










(1) 


N.A. 


N.A. 














Total Loss - 
Collector to 
StoTage and Loads 






Space Cooling 
Load 




Total Loss - 
Storage to Loads 


















* 


N.A. 


M-A. 





111 



* Denotes Unavailable Data 

N.A. denotes not applicable data 

(1) May contribute to offset of space heating load (if known - see text for discussion) 

D-8 



SO02 



APPENDIX E 
MONTHLY SOLAR ENERGY DISTRIBUTIONS 



The data tables provided in this appendix present an indication of solar 
energy distribution, intentional and unintentional, in the Chester West solar 
energy system. Tables are provided for 7 months of the reporting period. 






E-l 



TABLE E-l. SOLAR ENERGY DISTRIBUTION - SEPTEMBER 1978 

CHESTER WEST 

3.46 million Btu T()TAL SQLAR ENERGy C0LLECTED 



100% 

0.75 nm" ion Btu 

22% 

0.75 million Btu 



22% 



SOLAR ENERGY TO LOADS 

SOLAR ENERGY TO DHW SUBSYSTEM 



O.Q million Btu SQLAR ENERGY T0 spACE HEATING SUBSYSTEM 

/o 

N.A. million Btu $0LAR ENERGY T0 SPACE COOLING SUBSYSTEM 

10 

2.57 million Btu cn , fln nirnM , nffr , 

-j^o, SOLAR ENERGY LOSSES 



K, 



_2_J6_ million Btu SQLAR ENERGY LO ss FROM STORAGE 
lllion Btu SQLAR ENERGY L0SS IN TRANSPORT 



12% 

0.41 million Btu 
12% 

N.A. million Btu 



% 

N.A. million Btu 

% 

N.A. million Btu 



% 
N.A. million Btu 



COLLECTOR TO STORAGE LOSS 
COLLECTOR TO LOAD LOSS 

COLLECTOR TO DHW LOSS 

COLLECTOR TO SPACE HEATING LOSS 



COLLECTOR TO SPACE COOLING LOSS 



illion Btu STQRAGE T0 LQAD LQSS 



% 

N.A. mill ion Btu 



STORAGE TO DHW LOSS 



N.A. million Btu $T0RAGE JQ $pACE HEATING L0SS 

10 

N.A. million Btu, 



% 
0.14 million Btu 



'STORAGE TO SPACE COOLING LOSS 



4% 
i.A. - Denotes not applicable data c 



SOLAR ENERGY STORAGE CHANGE 



TABLE E-2. SOLAR ENERGY DISTRIBUTION - OCTOBER 1978 

CHESTER WEST 

_4j|7_ million Btu T()TAL $()LAR ENERGY COLLECTED 
_L97_ million Btu s0| _ AR £NERGY TQ im$ 

_L58_ million Btu SQLAR ENERGY T0 DHW SUBSYSTEM 
JL2|_ million Btu $0LAR ENERGY T0 SPACE HEATING SUBSYSTEM 
N.A. million Btu $0LAR ENERGY TQ SPACE c0 0LING SUBSYSTEM 

10 

_2J|_ million Btu $0LAR ENERGy L0SSES 

-LiL. million Btu SQLAR ENERGY L0SS FR0M STORAGE 
-Q^ZZ- million Btu s0| _ AR ENERGY L0SS IN TRA NSP0RT 

°'l8% mi11l ° n BtU C0LLECT0R TO STORAGE LOSS 
N.A. million Btu C0LLECT0R TQ LQAD LQSS 

10 

N.A. million Btu C0L| _ ECT0R T0 QHW LQSS 

lo 

N.A. million Btu C0LLECT0R JQ $pACE HEATING L0SS 
N.A. million Btu COL| _ ECTOR T0 SpACE C00LING L0SS 
N.A. million Btu ST0RAGE T0 LQAD L0$$ 

10 

_1^_ million Btu ST0RAGE TQ m lQ$s 
N.A. million Btu $T()RAGE JQ $pACE HEATING L0SS 

N.A. million Btu ST0RAGE T0 $pACE C00LING L0SS 

^ 

_0J^ million Btu $0LAR ENERQY ST0RAGE CHANGE 
N.A. - Denotes not applicable data E ' 3 



TABLE E-3. SOLAR ENERGY DISTRIBUTION - NOVEMBER 1978 

Chester West 

_K8|_ million Btu T0TAL SQLAp ENERGy C0LLECTED 
1.71 million Btu SQLAR ENERGy TQ LQA[)S 



92% 

0.51 million Btu 
27% 



SOLAR ENERGY TO DHW SUBSYSTEM 



JL20_ million Btu SQLAR ENERGY T0 SPACE HEATING SUBSYSTEM 
11 ion Btu SQLAR ENERGY T0 SPACE COOLING SUBSYSTEM 



% 
0.53 mill ion Btu 



29% 

0.18 mi" lion Btu 
10% 

0.35 million Btu 



SOLAR ENERGY LOSSES 

SOLAR ENERGY LOSS FROM STORAGE 
SOLAR ENERGY LOSS IN TRANSPORT 

COLLECTOR TO STORAGE LOSS 
COLLECTOR TO LOAD LOSS 

COLLECTOR TO DHW LOSS 



19% 

0.35 million Btu 

19% 

N.A. million Btu 



% 

N.A. mi" lion Btu, 



ill ion Btu CQLLECT0R TQ SpACE HEATING L0SS 



N.A. million Btu 



COLLECTOR TO SPACE COOLING LOSS 



ill ion Btu STQRAGE TQ LQAD LQSS 



% 

N.A. million Btu 



STORAGE TO DHW LOSS 



N.A. million Btu $T0RAGE T0 spACE HEATING L0S s 



NJl. million Btu STQRAGE TQ SpACE C00LING LO ss 



ill ion Btu s0| _ AR ENERGY STORAGE CHANGE 



-21 
. - Denotes not applicable data E-4 



TABLE E-4. SOLAR ENERGY DISTRIBUTION - DECEMBER 1978 

CHESTER WEST 

ill ion Btu T0TAL SQLAR ENERGY C0LLECTED 



100% 

* million Btu 



SOLAR ENERGY TO LOADS 
* million Btu 



% 
1.17 million Btu 



SOLAR ENERGY TO DHW SUBSYSTEM 



-gy^- SOLAR ENERGY TO SPACE HEATING SUBSYSTEM 

N.A. million Btu 



% 

* million Btu 

% 

* million Btu 



% 
0.28 million Btu 



SOLAR ENERGY TO SPACE COOLING SUBSYSTEM 
SOLAR ENERGY LOSSES 

SOLAR ENERGY LOSS FROM STORAGE 



SOLAR ENERGY LOSS IN TRANSPORT 
million Btu 



% 
million Btu 



% 



COLLECTOR TO STORAGE LOSS 
COLLECTOR TO LOAD LOSS 



JL. 

million Btu COLLECTOR JQ DHW LQSS 

10 

* million Btu 



% 
* million Btu 



% 
* million Btu 



% 

* million Btu 

°/ 

10 

* million Btu 



% 
* million Btu 



% 
0.05 million Btu 



COLLECTOR TO SPACE HEATING LOSS 
COLLECTOR TO SPACE COOLING LOSS 
STORAGE TO LOAD LOSS 

STORAGE TO DHW LOSS 

STORAGE TO SPACE HEATING LOSS 

STORAGE TO SPACE COOLING LOSS 



n 

* - Denotes unavailable data E-5 



SOLAR ENERGY STORAGE CHANGE 



TABLE E-5. SOLAR ENERGY DISTRIBUTION - JANUARY 1979 

CHESTER WEST 

lllion Btu T()TAL S0LAR ENERGY COLLECTED 



100% 

* mill ion Btu 



SOLAR ENERGY TO LOADS 
* million Btu 



% 
0.77 million Btu 



39% 
N.A. million Btu 



% 
* million Btu 



% 

* million Btu 

°i 

10 

0.19 million Btu 



SOLAR ENERGY TO DHW SUBSYSTEM 
SOLAR ENERGY TO SPACE HEATING SUBSYSTEM 
SOLAR ENERGY TO SPACE COOLING SUBSYSTEM 
SOLAR ENERGY LOSSES 

SOLAR ENERGY LOSS FROM STORAGE 
SOLAR ENERGY LOSS IN TRANSPORT 

COLLECTOR TO STORAGE LOSS 



10% 

0.19 million Btu 



ill ion Btu C0LLECT0R T0 L0AD LQSS 



% 

N.A. million Btu 



COLLECTOR TO DHW LOSS 



ill ion Btu C0| _ LECT0R T0 SpACE HEATING L0SS 



% 
N.A. million Btu 



COLLECTOR TO SPACE COOLING LOSS 



ill ion Btu STQRAGE T0 LQAD L0SS 



% 

N.A. million Btu 

% 

N.A. million Btu 



% 
N.A. million Btu 



% 
0.0 million Btu, 



STORAGE TO DHW LOSS 

STORAGE TO SPACE HEATING LOSS 

STORAGE TO SPACE COOLING LOSS 



'SOLAR ENERGY STORAGE CHANGE 
* - Denotes unavailable data E _g 



TABLE E-6. SOLAR ENERGY DISTRIBUTION - FEBRUARY 1979 

CHESTER WEST 

lllion Btu T0TAL S0LAR ENERGY COLLECTED 



100% 

* million Btu 



% 

* million Btu 

% 

0.86 million Btu 



39% 
N.A. million Btu 



% 
* million Btu 



SOLAR ENERGY TO LOADS 

SOLAR ENERGY TO DHW SUBSYSTEM 

SOLAR ENERGY TO SPACE HEATING SUBSYSTEM 

SOLAR ENERGY TO SPACE COOLING SUBSYSTEM 



SOLAR ENERGY LOSSES 
* million Btu 



SOLAR ENERGY LOSS FROM STORAGE 



lllion Btu SQLAR ENERGY L0SS IN TRANS port 



6% 



lllion Btu C0LLECT0R T0 storage LOSS 



6% 
N.A. million Btu 



% 

N.A. mil ion Btu 

% 

N.A. mil ion Btu 



% 
N.A. million Btu 



% 
N.A. million Btu 



% 

N.A. million Btu 

% 

N.A. million Btu 



% 
N.A. million Btu 



COLLECTOR TO LOAD LOSS 

COLLECTOR TO DHW LOSS 
COLLECTOR TO SPACE HEATING LOSS 
COLLECTOR TO SPACE COOLING LOSS 
[ TO LOAD LOSS 
STORAGE TO DHW LOSS 
STORAGE TO SPACE HEATING LOSS 
STORAGE TO SPACE COOLING LOSS 



ill ion Btu $0LAR ENERGY ST0RAGE CHANGE 



3% 



- Denotes unavailable data E-7 
N.A. - Denotes not applicable data 



TABLE E-7. SOLAR ENERGY DISTRIBUTION - MARCH 1979 

CHESTER WEST 

3.74 million Btu T()TAL SQ| _ AR ENERQY C0L| _ ECTED 



100% 

* mil 1 ion Btu 



SOLAR ENERGY TO LOADS 
* million Btu 



% 
0.73 million Btu 



20% 
N.A. million Btu 



% 
* million Btu 



% 

* million Btu 

% 

* million Btu 



SOLAR ENERGY TO DHW SUBSYSTEM 
SOLAR ENERGY TO SPACE HEATING SUBSYSTEM 
SOLAR ENERGY TO SPACE COOLING SUBSYSTEM 
SOLAR ENERGY LOSSES 

SOLAR ENERGY LOSS FROM STORAGE 
SOLAR ENERGY LOSS IN TRANSPORT 

COLLECTOR TO STORAGE LOSS 
COLLECTOR TO LOAD LOSS 

COLLECTOR TO DHW LOSS 



% 

* million Btu 

% 

N.A. million Btu 



% 

N.A. million Btu, 



ill ion Btu C0LLECT0R T0 SRACE HEATING L0SS 



% 
N.<\. million Btu 



% 
N.A. million Btu 



% 

N.A. million Btu 

% 

N.A. million Btu 



% 
N.A. million Btu 



In 



COLLECTOR TO SPACE COOLING LOSS 
STORAGE TO LOAD LOSS 

STORAGE TO DHW LOSS 

STORAGE TO SPACE HEATING LOSS 

STORAGE TO SPACE COOLING LOSS 



ill ion Btu SQLAR ENERGY STORAGE CHANGE 



6% 

* - Denotes unavailable data ^"^ 
N.A. - Denotes not applicable data 



nS^^H-OHIDA 



3 1 262 05391 1 



870